Night vision device, improved image intensifier tube for such a device having reduced particulate contamination and method of making

Abstract

A night vision device includes an improved image intensifier tube providing an image with reduced dark spots caused by microscopic particulate contamination in the tube. A method of processing image intensifier tubes to reduce dark spots caused by such microscopic particulate contamination within the tubes is disclosed.

I claim: 
     
       1. A method of making a night vision device having an improved image intensifier tube which provides an image with a reduced number of dark spots caused by microscopic particulate contamination within the image intensifier tube, said method comprising steps of: assembling and sealing said image intensifier tube to capture a vacuum within the chamber of the tube;   applying an acceleration to said image intensifier tube having a component parallel to a microchannel plate of the tube; and   using said acceleration to move a microscopic particulate contaminate within said tube away from an active area of the microchannel plate.   
     
     
       2. The method of claim 1 wherein said step of applying the acceleration to the image intensifier tube is selected from the group consisting of: spinning the image intensifier tube about its own optical axis, spinning the image intensifier tube about an axis spaced from the tube's own optical axis; moving the image intensifier tube linearly to a zone of sudden deceleration, moving the image intensifier tube arcuately to a zone of sudden deceleration, and dropping the image intensifier tube under gravitational acceleration to a zone of sudden deceleration. 
     
     
       3. The method of claim 1 further including the step of applying a vibrational input to the image intensifier tube. 
     
     
       4. The method of claim 3 further including the step of applying the vibrational input to the image intensifier tube simultaneously with the application of the acceleration parallel to the microchannel plate. 
     
     
       5. A method of processing an image intensifier tube in order to move a microscopic particulate contaminant within the tube, said method comprising steps of: applying an acceleration to the image intensifier tube, this acceleration having a component substantially parallel to a microchannel plate of the tube; and   using said acceleration to move a microscopic particulate contaminate within the tube.   
     
     
       6. The method of claim 5 further including providing an outer peripheral portion of a chamber within the tube, and moving the particulate contaminant away from an active area of the microchannel plate and toward this peripheral portion of the chamber. 
     
     
       7. The method of claim 5 wherein said step of applying the acceleration to the image intensifier tube includes spinning the image intensifier tube about its own optical axis. 
     
     
       8. The method of claim 5 wherein said step of applying the acceleration to the image intensifier tube includes centrifuging the image intensifier tube about an axis spaced from the tube's own optical axis. 
     
     
       9. The method of claim 5 wherein said step of applying the acceleration to the image intensifier tube includes accelerating the tube and then stopping its motion suddenly. 
     
     
       10. The method of claim 9 wherein the sudden stopping of the image intensifier tube is effected by applying a deceleration force to the tube. 
     
     
       11. The method of claim 5 further including the step of applying a vibrational input to the image intensifier tube. 
     
     
       12. The method of claim 11 further including the step of applying the vibrational input to the image intensifier tube simultaneously with the application of the acceleration parallel to the microchannel plate. 
     
     
       13. The method of claim 5 wherein said step of applying the acceleration to the image intensifier tube includes applying a combinational acceleration to the image intensifier tube. 
     
     
       14. A method of making a night vision device with fewer dark spots in an image provided by the device, said method comprising steps of: providing an objective lens;   providing an image intensifier tube;   utilizing the objective lens to focus light from a scene on a light-receiving surface of the image intensifier tube;   utilizing the image intensifier tube to responsively provide an image replicating the scene;   providing an eye piece lens to produce for a user of the device a virtual image replicating the scene;   subjecting the image intensifier tube to an acceleration having a component substantially parallel to a microchannel plate of the tube; and   utilizing the acceleration to move a particulate contaminant within the tube away from an active areas of the tube.